United States Patents
The present invention relates to an electromagnetic power generator and in particular to an electrical power generator intended for installation within a vehicular tire. Such electrical power generator can supply electrical power to energize a pressure sensor and a high frequency radio transmitter for monitoring tire air-pressure while traveling. Incorrect low tire pressure may cause, while traveling, tire rupture and an accident. Such system is described in U.S. Pat. No. 4,220,907, electromagnetic power generator, by Dennis G. Pappas et al. A change in the mechanical form of a vehicular tire, while traveling, is utilized for opening and closing a magnetic circuit thus generating electrical power. Another system for generating electrical power utilizing ferrofluid is described in U.S. Pat. No. 4,064,409, by Charles M. Redman. Thermal energy is converted into electrical power using flow of magnetized ferrofluid through a coil. An additional system utilizing ferrofluid and a permanent magnet is described in U.S. Pat. 5,632,093 by Sharon A. Elias, where mechanical vibrations are converted into an electrical voltage.
The ferrofluidic, electrical power generators constructed in accordance with the principles of the present invention consists of: an elongated, axially polarized permanent magnet; an electrical coil wound of insulated, electrically conductive wire disposed about a portion of said permanent magnet, and a double wall, cylindrical, sealed hollow hub housing made of non-magnetic material partially filled with ferrofluid. The assemblage of the permanent magnet and coil is firmly attached within said housing forming a magnetic circuit encompassed by said coil. Axial agitation of the magnetized ferrofluid will generate cyclic variations in the magnetic flux density causing induction in the electrical coil, generating electrical power.
Said electromagnetic power generator may be firmly attached to the outer steel rim of a vehicular tire. Rotation and horizontal velocity of said tire will cause agitation of the magnetized ferrofluid within the sealed housing and therefore, induction in the electrical coil.
In view of the above it is the principal object of the present invention to provide an electromagnetic power generator to power a pressure sensor and radio transmitter for the purpose of monitoring air pressure within the tire while the vehicle is in motion.
A further object is to provide such a device which may be small in size reliable, with no movable solid mechanical components. Such device generates electric power when firmly attached to an agitating object. A still further object is to provide such a device, which is simple in design and easy to manufacture. The above objects and advantages are attained with the present invention by providing five embodiments of a ferrofluidic, electrical power generator.